Measuring the avoidance behaviour shown by the snail Hydrobia ulvae exposed to sediment with a known contamination gradient

Abstract

This study tested the hypothesis that the snail Hydrobia ulvae will recognise differences in the contamination levels of sediment and avoid the more contaminated zones. Instead of testing avoidance behaviour in a two-compartment system, a linear contamination gradient has been devised in which several zones containing sediment with different contamination levels could be "chosen". A sediment of known severe contamination was collected and mixed with a non-toxic sediment to comprise a linear gradient with four concentrations of 0, 30, 60 and 100% contamination. Thus, the individuals were free to move between fields of different concentration (unforced conditions). During 24 h of exposure, the distribution of the organisms on fields was recorded and organisms' percentage that avoided each field was calculated for each concentration. At 30 and 60% of contamination, avoidance was around 50% for all periods of exposure. Avoidance at 100% contamination ranged between 11 and 56% (rates lower than expected). Organisms that did not avoid the 100% contamination revealed that they were inactive, indicating either that non-mobility and retraction within their shell may be alternative defence strategies, or else the high contamination may have impaired their ability to escape. The percentage of preference shown to the uncontaminated sediment ranged between 64 and 74%. The initial hypothesis was supported: H. ulvae avoids the more contaminated sediment. The assay proposed has been shown to be simple, rapid and effective; in addition, it is considered ecologically useful since the effects resulting from the avoidance are similar to the extinction of the population.

Impact of mercury contamination on the population dynamics of Peringia ulvae (Gastropoda): Implications on metal transfer through the trophic web

“…However, this fact is contrary to most of the macrobenthic species which usually present lower abundances and biomasses in the most contaminated areas (Mucha et al, 2005;Calabretta and Oviatt, 2008;Amin et al, 2009). Also, the present work is contrary to the findings of Araújo et al (2012), which found that Peringia ulvae when exposed to sediments with different degrees of contamination (including several contaminants) avoided the most contaminated sediments by escaping to the least contaminated ones. Indeed, the greater the percentage of sediments' contamination the greater the percentage of avoidance of snails and even the organisms presented in 100% contaminated sediments suffered a reduction in their activities (Araújo et al, 2012).…”

“…Also, the present work is contrary to the findings of Araújo et al (2012), which found that Peringia ulvae when exposed to sediments with different degrees of contamination (including several contaminants) avoided the most contaminated sediments by escaping to the least contaminated ones. Indeed, the greater the percentage of sediments' contamination the greater the percentage of avoidance of snails and even the organisms presented in 100% contaminated sediments suffered a reduction in their activities (Araújo et al, 2012). Table 2 Growth production estimations and associated mercury available for trophic transfer in P. ulvae in the 3 stations.…”

The Future of Benthic Indicators: Moving up to the Intertidal

“…Modifications in the behaviour, phenotype, metabolism or isotopic composition of intertidal invertebrates might be useful to detect non-natural changes in relation with e.g. alien species introduction [77,78], topographic modifications [79], the presence of plastic litter [80], metal contamination in sediment [81], exposition to pesticides [82,83], acidification [84,85] and temperature increase [86][87][88]. Furthermore, tools usually used to trace organic matter in the trophic network (i.e.…”

Impacts of particulate matter (PM2.5) on the behavior of freshwater snail Parafossarulus striatulus

“…However, this study used a different approach - behavioral examination, because the results of behavioral observations can be used to evaluate sub-lethal effects caused by environmental toxicity, which cannot be studied using LD 50. Sub-lethal analysis can be more informative than lethal dose experiments, because such approach allows a way to view the effects of the test chemicals on the behavior of the organism, which can have far-reaching ecological consequence 32–36 . To that end, small freshwater snails, Parafossarulus striatulus , were used as subjects for the experiment, partially because of their small and practical size, as well as their sensitivity to changes in their environment 37 .…”